Most of us think that moral norms are binding on us. For example, “Don’t kill a child for pleasure” is not a rule we can simply choose to follow or not, depending on our current desires and attitudes. Indeed, one point of the institution of morality seems to be to subordinate our personal preferences to the common good. The authority of moral norms, and the precedence they take over our personal desires, is often indicated by stating that moral norms are “objective.” The objective nature of moral norms is also often contrasted with the “subjective” nature of our personal desires. I may prefer pistachios over cashews, but my personal tastes are clearly not binding on anyone else. They are my own preferences; they are subjective.